iGCSE Biology 2c: Enzymes

Front

What are enzymes?

Back

Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process.

Front

What is the role of activation energy in enzyme activity?

Back

Activation energy is the minimum energy required for a chemical reaction to occur. Enzymes lower this energy, allowing reactions to proceed more quickly.

Front

What does it mean for an enzyme to denature?

Back

Denaturation is the process where an enzyme loses its specific shape due to external factors like extreme pH or temperature, resulting in loss of function.

Front

How does temperature affect enzyme activity?

Back

Enzyme activity typically increases with temperature up to an optimum point, after which high temperatures can cause denaturation.

Front

What is the optimum pH for most enzymes?

Back

The optimum pH is the pH level at which an enzyme functions most effectively, usually around neutral (pH 7) for many enzymes.

Front

What happens to enzyme activity at extreme pH levels?

Back

Extreme pH levels can lead to denaturation of the enzyme, causing a significant drop in activity.

Front

How do enzymes affect the concentration of substrates?

Back

Enzymes do not change the concentration of substrates; they facilitate the conversion of substrates into products.

Front

What is substrate specificity in enzymes?

Back

Substrate specificity refers to the ability of an enzyme to choose exact substrates from a group of similar chemical molecules.

Front

What is the effect of enzyme concentration on reaction rate?

Back

Increasing enzyme concentration generally increases the reaction rate, provided there is enough substrate available.

Front

What is competitive inhibition?

Back

Competitive inhibition occurs when a substance similar to the substrate competes for the active site of the enzyme, reducing the rate of reaction.